Inhibitors of transcription of fungal glucan synthase

描述(申请人提供)：真菌细胞和人类细胞之间最显著的区别可能是真菌细胞被包裹在一层墙中，以保护它们免受渗透和免疫上不利的外部环境的影响。此外，真菌细胞壁传递可能的植物、动物或人类宿主入侵和感染的信号。细胞壁不是一层惰性的外层，而是在真菌生理的各个方面发挥着动态作用，如形态发生、代谢物运输、蛋白质分泌、细胞内信号转导和细胞与细胞的接触。现在，至少在子囊菌中，细胞壁结构已经很好地表征了，并且似乎在人类病原体中非常相似，包括白色念珠菌、青霉菌和曲霉。人类细胞缺乏细胞壁和形成细胞壁的基本生物合成和调节机制，这一事实表明，靶向细胞壁合成和组装的药物将是安全和特异的抗真菌药物。 目前治疗真菌感染的方法很少，包括与膜类固醇相互作用的两性霉素B，以及抑制膜类固醇生物合成的各种唑类和烯丙胺。不幸的是，两性霉素B对人类是有毒的，临床上对唑类药物的耐药性正在增加。这些观察结果强调了对新的抗真菌药物的明显需求。在这个第一阶段的SBIR应用中，我们建议开发一种新的筛选，以确定真菌细胞壁组装的关键基因的转录抑制物，即(1，3)β-葡聚糖合成酶活性的催化亚单位。这将通过两个具体目标来实现： 目的一：建立一种筛选编码(1，3)β-葡聚糖合成酶催化亚单位的FKS基因转录抑制物的方法。 目的二：筛选3,000个(1，3)β-葡聚糖合成酶FKS基因转录抑制物。重要的是，我们将确定假定的抑制剂对真菌生长、人类细胞毒性和FKS信息水平的影响。 这项工作将导致一种新的分析方法，将用于发现新的抗真菌化合物。反过来，这些新化合物将被开发用于治疗人类真菌疾病。

DESCRIPTION (provided by applicant): Perhaps the most striking difference between fungal cells and human cells is that fungal cells are encased in a wall that protects them from an osmotically and immunologically hostile external environment. In addition, the fungal cell wall relays signals for invasion and infection of a likely plant, animal, or human host. The cell wall is not an inert outer layer, but rather plays a dynamic role in all aspects of fungal physiology, e.g., morphogenesis, metabolite transport, protein secretion, intracellular signaling, and cell-cell contact. Cell-wall structure is now well characterized, at least in the ascomycetes, and appears to be very similar in human pathogens including Candida albicans, Penicillium spp., and Aspergillus spp. The fact that human cells lack a cell wall and the underlying biosynthetic and regulatory machinery to make the wall, suggests that drugs targeting cell-wall synthesis and assembly will be safe and specific antifungals. Current treatments for fungal infections are limited by few therapeutic options; these include amphotericin B, which interacts with membrane sterols, and a variety of azoles and allylamines that inhibit membrane sterol biosynthesis. Unfortunately, amphotericin B is toxic to humans and clinical resistance to azoles is increasing. These observations underscore the clear need for new antifungals. In this Phase I SBIR application, we propose to develop a novel screen that identifies inhibitors of transcription of a key gene for fungal cell-wall assembly, namely, the catalytic subunit of (1,3) beta-glucan synthase activity. This will be accomplished in two specific aims: Aim One: Development of a screen to identify inhibitors of transcription of the FKS gene encoding the catalytic subunit of (1,3) beta -glucan synthase. Aim Two: Screen 3,000 pure compounds for inhibitors of transcription of the (1,3) beta -glucan synthase FKS gene. Importantly, we will determine the effect of putative inhibitors on fungal growth, on human-cell toxicity, and on the levels of FKS message. This work will lead to a novel assay that will be used for the discovery of new antifungal compounds. In turn, these novel compounds will be developed for the treatment of human fungal diseases.